Vulcano Eyjafjallajokull a rischio eruzione!

[Stefano De C.]

Probabilmente un'eruzione violenta li raggiungerebbe e supererebbe! Come ha detto giustamente qualcuno , preoccupano maggiormente le nubi ardenti e le decina di migliaia di vittime che potrebbero provocare in una zona iperpopolata , nel caso di tardivo allarme o di evento improvviso ( ipotesi abbastanza scartabile, per fortuna)

Mi pare di aver sentito a superquark che l'eruzione del 79 d. C. venne preceduta da uno sciame sismico di 2 anni

[Storm93]

Nella scala VEI quant'è il Vesuvio??

[Stefano De C.]

Nella scala VEI quant'è il Vesuvio??

penso 6-7

[over the top]

Mi pare di aver sentito a superquark che l'eruzione del 79 d. C. venne preceduta da uno sciame sismico di 2 anni

Si ma si parla dello sgombero di un milione di persone! Non credo sia una cosa molto veloce e che venga attuata solo a causa di qualche leggera scossa

[Storm93]

penso 6-7

Grazie, in effetti ho trovato che il massimo è stato VEI 6.

[over the top]

Grazie, in effetti ho trovato che il massimo è stato VEI 6.

Dipende dall'Eruzione ovviamente!

[over the top]

Pare comunque che durante l'Eruzione di ercolano e Pompei la colonna possa aver raggiunto di 32 km

[Michele Boncristiano]

You mean on this graph?
http://forum.meteonetwork.it/imgcache/64879.gif

As far as I have read, those are the big earthquakes which can be seen like those peaks, but on the other hand its a bit harder to explain their long lasting period... I'd expect the peaks to be short time lasting if we have a classic earthquake, not for several hours

I've asked to me the same thing about time n the answer I gave me is that the tremor shown in that graph is a continuous series of very small accelerations...so u have constant acceleretion but very very small. Moreover in that graph r shown only positive acceleration's peaks (above time axis), for example the red line is probably a line connecting all maximum aceleration's peaks of red frequency, so it isn't the real accelerogram 'cos if it were the red line should go continuously above n below time axis in a very short time space (as an earthquake has both positive and negative accelerations) so you'd see red all the area above the red line ...maybe ...that's my reading, I know well accelerograms but that's the first time I see tremor graphs.
A clarification: these above are not acelerations but velocities (nm/s) but it's the same!!

[Aragorth]

I've asked to me the same thing about time n the answer I gave me is that the tremor shown in that graph is a continuous series of very small accelerations...so u have constant acceleretion but very very small. Moreover in that graph r shown only positive acceleration's peaks (above time axis), for example the red line is probably a line connecting all maximum aceleration's peaks of red frequency, so it isn't the real accelerogram 'cos if it were the red line should go continuously above n below time axis in a very short time space (as an earthquake has both positive and negative accelerations) so you'd see red all the area above the red line ...maybe ...that's my reading, I know well accelerograms but that's the first time I see tremor graphs.
A clarification: these above are not acelerations but velocities (nm/s) but it's the same!!

Immagine

I am not an expert for volcanos or seismology, so I was based on my physics knowledge. It seems that your explanation is good. For me those tremors looks like very rapid accelerations acting like micro vibrations I believe. And so they have several frequencyes to measure the power of them.
But really, I dont know lot about these things, so I hardly judge the graphs... but I like them

[Michele Boncristiano]

I am not an expert for volcanos or seismology, so I was based on my physics knowledge. It seems that your explanation is good. For me those tremors looks like very rapid accelerations acting like micro vibrations I believe. And so they have several frequencyes to measure the power of them.
But really, I dont know lot about these things, so I hardly judge the graphs... but I like them

The thing that I could not understand is why are not recorded earthquakes from that station (too few great peaks), probably the station filters only low-frequency and excludes real earthquakes